[Ietf-calsify] Issue 13: confusion in DTSTART text about "if specified" and BY rules

[Oliver Block]

Am Freitag, 13. Oktober 2006 12:29 schrieb Reinhold Kainhofer:

> Exactly. But the Andrew's proposal would add a cross dependency of set A on
> set B (as the COUNT of RRULE would depend on whether the DTSTART is in the
> final set R, which means that it is not in B).

Let's take your example from above:

Interpretation 1 (DTSTART is 1st occurance):
------------------------------------------------------
> >   DTSTART;VALUE=DATE:20061013
> >   RRULE:FREQ=WEEKLY;COUNT=3
> > This would last until Oct 27.

A = {20061013, 20061020, 20061027}
B = {}
R = A \ B means in this case R = A

> > Now add one simple EXDATE to exclude DTSTART:
> >   DTSTART;VALUE=DATE:20061013
> >   RRULE:FREQ=WEEKLY;COUNT=3
> >   EXDATE;VALUE=DATE:20061013

A = {20061013, 20061020, 20061027}
B = {20061013}
R = A \ B = {20061020, 20061027}

Interpretation 2 (1st occurance is first date generated by RRULE):
--------------------------------------------------------------------------------
> >   DTSTART;VALUE=DATE:20061013
> >   RRULE:FREQ=WEEKLY;COUNT=3
> > This would last until Oct 27.

A = {20061020, 20061027, 20061103}
B = {}
R = A \ B means in this case R = A

> > Now add one simple EXDATE to exclude DTSTART:
> >   DTSTART;VALUE=DATE:20061013
> >   RRULE:FREQ=WEEKLY;COUNT=3
> >   EXDATE;VALUE=DATE:20061013

A = {20061020, 20061027, 20061103}
B = {20061013}
R = A \ B = {20061020, 20061027, 20061103}

That's how I understand either of the interpretations.

Regards,

Oliver

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